Hello user

I will recommend You to look at this thread : https://helpcenter.websitex5.com/de/post/150540

You have the following obvious options for a calendar :

Object "full calendar" which I will not recommend unless You want a viewer( it is not a calendar - it is a viewer )

Google Calendar - a good calendar, but You will not use it.

Luxcal calendar - a very very good calendar - one of the best free web-calendars You can find.

Hope this helps You.

Kind regards

John S.